The present invention relates to a method and apparatus for converting heat energy of hot exhaust gases of a textile machine to a usable energy form.
Certain textile machines such as, for example, tenter frames, include treatment chambers into which heated air is introduced at operating temperatures well above normal room temperatures. The heated treatment chambers release heated exhaust gases during their operations and it is known to conduct these heated exhaust gases through cleaning devices and heat exchange devices to cleanse the exhaust gases of pollutants and then recapture a portion of their heat energy. For example, one known process for handling heated exhaust gases released from the treatment chamber of textile machines includes the initial step of heating the exhaust gases to a temperature approximately in the range of 500.degree. Celsius by conducting the gas through the tubes of a conventional heat exchanger. Thereafter, the now further heated exhaust gases are conducted into a conventional gas or oil-powered combustion chamber in which the gas is heated to a temperature approximately in the range of 750.degree. Celsius for a period of approximately one-half second, which is usually sufficient to effect combustion of substantially all of the contaminants and other pollutants of the exhaust gas.
After the combustion of the contaminants and other pollutants, the exhaust gases, which are now substantially comprised of unpolluted air, are conducted through the tubes of the same heat exchanger which initially heated the exhaust gases upon their exit from the treatment chamber. The travel of the exhaust gases through this heat exchanger effects a cooling of the gases to a temperature in the range of approximately 500.degree. Celsius, which is the temperature to which the initially exhausted gases are heated. Thereafter, the exhaust gases are conducted to another heat exchanger, which is operatively coupled to the treatment chamber, for extracting heat from the exhaust gases to effect heating of the air being introduced into the treatment chamber. This further heat exchange process further cools the exhaust gases to a temperature in the range of approximately 350.degree. Celsius, at which temperature the gases are normally released to the atmosphere.
Although the exhaust gases still retain considerable heat energy after passing through the last heat exchange process, there is typically no use made of this heat energy. Due to factors such as the cost of conducting exhaust gases to a remote location or the non-uniform energy demand for use of such exhaust gases for heating a room or the like, these exhaust gases are typically discharged to the atmosphere with the subsequent waste of their heat energy. Accordingly, the need exists for a method and apparatus to minimize the relative amount of unexpended heat energy still contained in the exhaust gases when the gases are released to the atmosphere.